Takashi Murashita, MD
Central Message
Further studies are needed to identify the optimal strategy for prevention of sudden cardiac death after coronary artery bypass grafting in patients with left ventricular dysfunction.
See Article page 163.
Sudden cardiac death (SCD) is a well-known complication after coronary revascularization in patients with left ventricular dysfunction. Implantable cardioverter-defibrillator (ICD) therapy is associated with a reduction in the rate of death due to life-threatening ventricular arrhythmia (VA). The SCD rate could be greatest in the early period of revascularization. However, previous studies failed to show survival benefit of prophylactic implantation of ICD at the time of coronary artery bypass grafting (CABG)
1
or early after acute myocardial infarction.2
,3
Therefore, a final decision on ICD implantation is typically deferred for 3 months after coronary revascularization.4
- Al-Khatib S.M.
- Stevenson W.G.
- Ackerman M.J.
- Bryant W.J.
- Callans D.J.
- Curtis A.B.
- et al.
2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines and the Heart Rhythm Society.
J Am Coll Cardiol. 2018; 72: 91-220
In this issue of the Journal, Nakae and colleagues
5
reviewed 498 patients with ejection fraction <40% who underwent CABG and investigated the clinical impact of ICD placement on patients' postoperative survival. Ninety-nine patients (20%) developed postoperative VA; 46 symptomatic ventricular tachycardia (VT), 27 asymptomatic sustained VT, and 26 nonsustained VT. Of 99 patients who had postoperative VA, 55 patients received ICD; 28 received within 3 months of CABG, 27 received after 3 months of CABG, and no patient received concomitant ICD implantation at the time of CABG. Nakae and colleagues5
reported a survival benefit for patients with VAs who received ICD implantation.Nakae and colleagues
5
provide interesting and potentially useful information for cardiac surgeons and their coworkers who take care of patients with ischemic cardiomyopathy. However, there are still some unanswered questions regarding ICD implantation after CABG.First, in this paper of Nakae and colleagues,
5
approximately one-half of the patients underwent ICD within 3 months of the operation, which was more aggressive than guideline recommendations. Currently, a wearable cardioverter defibrillator (WCD) has been widely used to close the gap between coronary revascularization and ICD implantation. WCD could work as a bridge to left ventricular function improvement. Although the survival benefit of WCD after coronary revascularization was reported,6
,- Zishiri E.T.
- Williams S.
- Cronin E.M.
- Blackstone E.H.
- Ellis S.G.
- Roselli E.E.
- et al.
Early risk of mortality after coronary artery revascularization in patients with left ventricular dysfunction and potential role of the wearable cardioverter defibrillator.
Circ Arrhythm Electrophysiol. 2013; 6: 117-128
7
there is no established evidence regarding the superiority of WCD over early ICD implantation (within 90 days).Second, although Nakae and colleagues
5
reported the clinical benefit of ICD implantation both in life-threatening VA and hemodynamically stable VA, whether the ICD implantation should be indicated to asymptomatic sustained VT or nonsustained VT is debatable. This study was a retrospective, multicenter study; therefore, a decision of ICD implantation was at the discretion of the heart team in each institute.Third, the leading cause of death in this study was heart failure, which was followed by SCD. Neither ICD nor WCD itself would improve the cardiac function. However, one can assume that cardiac resynchronization therapy defibrillator might provide a positive impact on patients' outcome by both improving cardiac function and preventing SCD. There is no established evidence of early application of cardiac resynchronization therapy defibrillator after coronary revascularization.
The randomized controlled trial that investigated the efficacy of prophylactic ICD at the time of CABG was performed in 1997, and it was before the advent of WCD. Another randomized controlled trial comparing the WCD and early ICD implantation would be warranted.
References
- Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary-artery bypass graft surgery. Coronary Artery Bypass Graft (CABG) Patch Trial Investigators.N Engl J Med. 1997; 337: 1569-1575
- Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction.N Engl J Med. 2004; 351: 2481-2488
- Defibrillator implantation early after myocardial infarction.N Engl J Med. 2009; 361: 1427-1436
- 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines and the Heart Rhythm Society.J Am Coll Cardiol. 2018; 72: 91-220
- Ventricular arrhythmias following coronary artery bypass grafting for ischemic cardiomyopathy: when to insert an implanted cardioverter defibrillator?.J Thorac Cardiovasc Surg Open. 2023; 13: 163-175
- Early risk of mortality after coronary artery revascularization in patients with left ventricular dysfunction and potential role of the wearable cardioverter defibrillator.Circ Arrhythm Electrophysiol. 2013; 6: 117-128
- Wearable cardioverter defibrillator multicentre experience in a large cardiac surgery cohort at transient risk of sudden cardiac death.Eur J Cardio Thorac Surg. 2022; 61: 1031-1040
Article info
Publication history
Published online: November 25, 2022
Accepted:
November 21,
2022
Received:
November 17,
2022
Footnotes
Disclosures: The author reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
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© 2022 The Authors. Published by Elsevier Inc. on behalf of The American Association for Thoracic Surgery
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